The present invention relates to a display module and, more particularly, to the structure of a display panel suitable for a thin display panel of a television.
As an example of a display module, liquid crystal display modules have been developed suitable for providing television displays. The liquid crystal display modules are thin enough to provide portable television sets.
The liquid crystal display modules suitable and applicable to the television sets can be classified into two types:
1. Active matrix display type comprising a liquid crystal cell for providing a display surface, and a silicon substrate for carrying a driver, the silicon substrate being disposed on a rear substrate of the liquid crystal cell. PA0 2. Timesharing operation display type which has evolved from the origin of the conventional electronic calculator display or electronic timepiece display. PA0 The number of picture elements: 120.times.180 PA0 The picture size: 46.1 mm.times.61.4 mm PA0 The number of the scan lines: 120/4=30 PA0 The number of the signal lines: 5/mm (200 .mu.m pitch), (180.times.4=320 lines in a 61.4 mm interval.)
The present invention is concerned with the timesharing operation display type.
FIG. 1 shows the structure of a conventional timesharing operation display module. This module comprises a liquid crystal display cell 1, a flexible circuit plate 2, a circuit board 3, circuit components 4, flexible wiring lines 5, and wiring lines 6. The flexible wiring lines 5 on the flexible circuit plate 2 serves to electrically connect the liquid crystal display cell 1, and the circuit components 4 and the wiring lines 6 both on the circuit board 3.
In the above arrangement of the display module of FIG. 1, the display module cannot be thin and compact since the flexible circuit plate 2 is bent to occupy useless space.
Another aspect is that a matrix type display requires 10,000 picture elements to provide television-like pictures. For this requirement, about 100 or more scan lines are required in a simple or a non-multiplex matrix display. However, an exact picture display cannot be expected by using so many scan lines.
Therefore, in the timesharing operation display type, it is urged that the number of lines leading from the liquid crystal display cell should be reduced. For this purpose, the multiplex degree of the timesharing operation is increased. When the multiplex degree is N, the number of scan lines is 1/N times as small as that of the scan lines in the simple or the non-multiplex matrix display, but the number of signal lines is N times as large as that of the signal lines in the simple or the non-multiplex matrix display.
The scan lines are connected to scan electrodes disposed on a rear substrate of the liquid crystal display cell. The signal lines are connected to signal electrodes disposed on a front substrate forming a display surface of the display cell.
Then, increasing the multiplex degree beyond an appropriate degree leads to the problem of handling the many terminals of the signal lines and of generating cross talk. Therefore, the following tetra-multiplexing degree is proposed which appears to be in practice.
However, conventional structures of the liquid crystal display module cannot assure the above connection density of the lines, exactly.